1. Field of the Invention
This invention relates to an image forming apparatus using the electrophotographic process such as a laser beam printer, a copier or a facsimile apparatus, and a process cartridge mounted on the image forming apparatus.
Here, the process cartridge refers to at least one of charging means, developing means and cleaning means and an electrophotographic photosensitive body integrally made into a cartridge which is detachably attachable to the main body of an electrophotographic image forming apparatus, or at least developing means and an electrophotographic photosensitive body integrally made into a cartridge which is detachably attachable to the main body of an electrophotographic image forming apparatus.
2. Related Background Art
In an image forming apparatus of the electrophotographic type such as a copier or a laser beam printer, light corresponding to image information is applied to an electrophotographic photosensitive body to thereby form an electrostatic latent image thereon, and a developer (toner) which is a recording agent is supplied to this electrostatic latent image by developing means to thereby visualize the latent image, and further the image is transferred from the electrophotographic photosensitive body to a recording medium such as recording paper to thereby form an image on the recording paper.
In such an image forming apparatus, with a view to achieve the simplicity of the interchange maintenance of expendables such as the electrophotographic photosensitive body and the toner, a toner containing portion, the developing means, the electrophotographic photosensitive body, charging means, cleaning means including a waste toner container, etc. are often made integral as a process cartridge which is made detachably attachable to the main body of the image forming apparatus.
Also, there is an apparatus like a color image forming apparatus which has developing means of a plurality of colors and in which, in order to cope with a case where the degrees of consumption of the respective developing means differ from one another or a case where the degree of consumption of the electrophotographic photosensitive body and the degrees of consumption of the developing means differ from each other, individual means are made into cartridges such as respective color developing cartridges, i.e., developing apparatuses made into cartridges, and a photosensitive body cartridge into which cleaning means and the electrophotographic photosensitive body are integrally made.
There is also an apparatus in which storing means (memories) are carried on these cartridges to thereby control cartridge information. As described in U.S. Pat. No. 5,272,503, there is also an apparatus in which the used amount of a cartridge is stored to thereby change various process conditions. For example, the charging current value is changed over or the exposure amount is adjusted. In these apparatuses, if in spite of the cartridges differing from one another, the used amounts thereof are the same the same control is done.
However, if the image forming apparatus becomes complicated, there will more or less come out the instability of the manufacturing lot, color difference, etc. of the electrophotographic photosensitive body and toners and the difference in characteristic due to the manufacturing lots of individual cartridges. Also, the characteristic is varied by a user""s using state and images cannot be always outputted with the same quality. Also, according to the prior art, it has been insufficient to correct any variation in the quality of image in all cartridges.
Accordingly, it is an object of the present invention to provide an electrophotographic image forming apparatus and a process cartridge which can obtain images of a stable quality of image in conformity with the individual characteristic of the process cartridge by a simple and inexpensive construction.
It is another object of the present invention to provide an electrophotographic image forming apparatus and a process cartridge which can calculate the used amount of the process cartridge by obtaining the individual characterics of the process cartridge from the individual characteristic information of the process cartridge stored in storing means and the history information thereof accumulated with use, and obtain stable images of a high quality conforming to individual characteristics of the process cartridge.
In order to achieve the above objects, the image forming apparatus according to the present invention is an electrophotographic image forming apparatus permitting a process cartridge to be mounted thereon and for forming an image on a recording medium, comprising:
(a) a mounting means for detachably mounting a process cartridge having an electrophotographic photosensitive body, a process means for acting on the electrophotographic photosensitive body, and a storing means for storing the history information of the electrophotographic photosensitive body therein;
(b) a driving means for moving the surface of the electrophotographic photosensitive body;
(c) a charging voltage power supply for applying a voltage to charging means for uniformly charging the surface of the electrophotographic photosensitive body; and
(d) a transferring voltage power supply for applying a voltage to a transferring means for transferring an image formed on the electrophotographic photosensitive body by the process means to the recording medium;
(e) a reading means for reading out the history information stored in the storing means;
(f) a detecting means for detecting use information of the electrophotographic photosensitive body in the main body of the electrophotographic image forming apparatus subsequent to the time period of the stored history information;
(g) a calculating means for calculating the latest history information from the stored history information and the use information;
(h) a writing means for writing the latest history information into the storing means; and
(i) a control means for changing image forming process conditions on the basis of the history information in the storing means.
According to an embodiment of the present invention, the storing means has individual information regarding the manufacturing lots or kinds of at least one of the process cartridge, a developer, the electrophotographic photosensitive body, the process means for acting on the electrophotographic photosensitive body, and functional members included in the process means.
According to another embodiment of the present invention, the electrophotographic image forming apparatus has a calculation means for calculating the frequency of use of the electrophotographic photosensitive body on the basis of the history information of the electrophotographic photosensitive body and the individual information of the process cartridge stored in the storing means, and a control means for changing the image forming process conditions according to the calculated frequency of use of the electrophotographic photosensitive body.
According to another embodiment of the present invention, the electrophotographic image forming apparatus has a calculation means for calculating the frequency in use of the electrophotographic photosensitive body, and a control means for changing the image forming process conditions on the basis of the calculated frequency in use of the electrophotographic photosensitive body and the individual information of the process cartridge.
According to another embodiment, the electrophotographic image forming apparatus has a conversion expression or a conversion table for converting each bit of individual information of the process cartridge into the frequency in use of the electrophotographic photosensitive body and image forming process conditions conforming to the used amount.
According to another embodiment, the process cartridge comprising a cartridge in which at least one of a charging means, a developing means and a cleaning means as the process means and the electrophotographic photosensitive body are put together and the cartridge is made detachably attachable to the main body of the electrophotographic image forming apparatus.
Another image forming apparatus according to the present invention is an electrophotographic image forming apparatus for forming an image on a recording medium, characterized by:
an electrophotographic photosensitive body;
a process means for acting on the electrophotographic photosensitive body;
a storing means for storing the history information of the electrophotographic photosensitive body therein;
a driving means for moving the surface of the electrophotographic photosensitive body;
a charging voltage power supply for applying a voltage to a charging means for uniformly charging the surface of the electrophotographic photosensitive body;
a transferring voltage power supply for applying a voltage to a transferring means for transferring an image formed on the electrophotographic photosensitive body by the process means to the recording medium;
a reading means for reading out the history information stored in the storing means;
a detecting means for detecting the use information of the electrophotographic photosensitive body in the main body of the image forming apparatus subsequent to the time period of the stored history information;
a calculating means for calculating the latest history information from the stored history information and the use information;
a writing means for writing the latest history information into the storing means; and
a control means for changing image forming process conditions on the basis of the history information in the storing means.
According to an embodiment of each of the above-described inventions, the electrophotographic image forming apparatus further has changing means for changing the surface moving speed of the electrophotographic photosensitive body into a surface speed of a plurality of stages when image formation is effected.
According to another embodiment of each of the above-described inventions, the electrophotographic image forming apparatus further comprises a changing means for changing the charging voltage into a charging voltage of a plurality of stages when an image is formed.
According to another embodiment, the electrophotographic image forming apparatus further comprises a changing means for changing a transferring voltage into a transferring voltage of a plurality of stages when an image is formed.
According to another embodiment, the history information stored in the storing means in the electrophotographic image forming apparatus is at least one of a total driving time of the electrophotographic photosensitive body, a total charging time applied to the electrophotographic photosensitive body, and a total transferring time applied to the electrophotographic photosensitive body.
According to another embodiment, the history information stored in the storing means is at least one of a driving time of the electrophotographic photosensitive body at each changed surface moving speed, a charging time under each changed charging voltage condition, and a transferring time under each changed transferring voltage condition.
According to another embodiment, the electrophotographic image forming apparatus comprises a calculation means for calculating frequency in use of the electrophotographic photosensitive body from the history information of the electrophotographic photosensitive body stored in the storing means, and control means for changing image forming process conditions according to the calculated frequency in use of the electrophotographic photosensitive body.
According to another embodiment, the electrophotographic image forming apparatus has a means for calculating the frequency T in use of the electrophotographic photosensitive body on the basis of a calculation expression that
T=k1xc3x97t1+k2+t2+k3xc3x97t3+k1xe2x80x2xc3x97t1xe2x80x2+k2xe2x80x2xc3x97t2xe2x80x2+ . . . +xcex1
(where k1, k1xe2x80x2, . . . k2, k2xe2x80x2, . . . , k3, k3xe2x80x2, . . . xe2x89xa70) by the use of predetermined coefficients k1, k1xe2x80x2, k1xe2x80x3, . . . , k2, k2xe2x80x2, k2xe2x80x3, . . . , k3, k3xe2x80x2, k3xe2x80x3, . . . , xcex1 when the driving times of the electrophotographic photosensitive body at respective surface moving speeds which are the history information in the storing means are defined as t1, t1xe2x80x2, t1xe2x80x3, . . . , and the charging voltage applying times under respective charging voltage conditions are defined as t2, t2xe2x80x2, t2xe2x80x3, . . . , and the transferring voltage applying times under respective transferring voltage conditions are defined as t3, t3xe2x80x2, t3xe2x80x3, . . . .
According to another embodiment, the electrophotographic image forming apparatus uses a conversion expression or a conversion table for converting the frequency in use of the electrophotographic photosensitive body into image forming process conditions conforming to the used amount.
A process cartridge according to the present invention is a process cartridge detachably attachable to the main body of an electrophotographic image forming apparatus, comprising an electrophotographic photosensitive body, a process means for acting on the electrophotographic photosensitive body, and a storing means for storing the history information of the electrophotographic photosensitive body therein, wherein at least one of a charging means, a developing means or a cleaning means as the process means and the electrophotographic photosensitive body are put into a cartridge together.
According to an embodiment of the present invention, the storing means has at least individual information regarding manufacturing lots or kinds of at least one of the process cartridge, a developer, the electrophotographic photosensitive body, the process means for acting on the electrophotographic photosensitive body, and a functional member included is the process means.
According to another embodiment, the history information stored in the storing means of the process cartridge is at least one of a total driving time of the electrophotographic photosensitive body, a total charging time applied to the electrophotographic photosensitive body, and a total transferring time applied to the electrophotographic photosensitive body.
According to another embodiment, the history information stored in the storing means of the process cartridge is at least one of a driving time of the electrophotographic photosensitive body at each changed surface moving speed, a charging time under each changed charging voltage condition, and a transferring time under each changed transferring voltage condition.
According to another embodiment, the storing means of the process cartridge stores therein a calculation expression for calculating the frequency in use of the electrophotographic photosensitive body conforming to the individual information from the history information of the electrophotographic photosensitive body.
According to another embodiment, the storing means stores therein a conversion expression or a conversion table for converting the frequency in use of the electrophotographic photosensitive body into image forming process conditions conforming to the used amount.
According to another embodiment, the storing means of the process cartridge stores therein a conversion expression or a conversion table for converting the frequency in use of the electrophotographic photosensitive body into image forming process conditions conforming to the individual information and the frequency.
According to another embodiment, the storing means of the process cartridge stored therein at least one of coefficients k1, k1xe2x80x2, . . . , k2, k2xe2x80x2, . . . , k3, k3xe2x80x2, . . . , xcex1 when frequency T in use of the electrophotographic photosensitive body is calculated on the basis of a calculation expression that
T=k1xc3x97t1+k2xc3x97t2+k3xc3x97t3+k1xe2x80x2xc3x97t1xe2x80x2+k2xe2x80x2xc3x97t2xe2x80x2+ . . . xcex1
(where k1, k1xe2x80x2, . . . , k2, k2xe2x80x2, . . . , k3, k3xe2x80x2, . . . xe2x89xa70)
by the use of predetermined coefficients k1, k1xe2x80x2, k1xe2x80x3, . . . , k2, k2xe2x80x2, k2xe2x80x3, . . . ,k3, k3xe2x80x2,k3xe2x80x3, . . . , xcex1 when the driving times of the electrophotographic photosensitive body at respective surface moving speeds which are the history information the storing means of the process cartridge has therein are defined as t1, t1xe2x80x2, t1xe2x80x3, and the charging voltage applying times under respective charging voltage conditions are defined as t2, t2xe2x80x2, t2xe2x80x3, . . . , and the transferring voltage applying times under respective transferring voltage conditions are defined as t3, t3xe2x80x2, t3xe2x80x3, . . . .
According to another embodiment, the storing means of the process cartridge stores therein the frequency T in use of the electrophotographic photosensitive body.
The electrophotographic image forming apparatus and process cartridge of the present invention have a reading means for reading out the history information stored in the storing means of the process cartridge, detecting means for detecting the subsequent use information of the electrophotographic photosensitive body in the main body of the image forming apparatus from the stored history information, a calculating means for calculating the latest history information from the stored history information and the use information, a writing means for writing the latest history information into the storing means, and a control means for changing the image forming process conditions on the basis of the history information in the storing means, and thereby can effect the proper control of the process conditions by the use situation of the electrophotographic photosensitive body in conformity with the characteristics of individual process cartridges, and accordingly can obtain stable images of a high quality. Further, they can calculate the used amount of the process cartridge having absorbed the individual difference of the process cartridge thereinto by the individual information of the process cartridge stored in the storing means, and the history information accumulated with the use, and can obtain stable images of a high quality in conformity with individual characteristics.
Other objects and aspects of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings.